Anisotropic Compressive Properties and Energy Absorption Efficiency of Porous Twisted Short Fiber Materials

Abstract

Novel stainless steel porous twisted short fiber materials (PTSFMs) with spatial composite intertexture structure are produced by compaction following with sintering of twisted short fibers. The stainless steel twisted short fibers are fabricated using a cutting stainless steel fiber ropes method with a self-developed rotary multi-cutter tool. The porous structure of the stainless steel PTSFMs exhibits a large difference in the through-thickness and in-plane direction, which results in differences in compressive behavior. During the compressive process, it is determined that the stainless steel PTSFMs exhibit typical elastic-plastic behaviors (three deformation stages) in the in-plane direction, but in the through-thickness direction, entered the compact densification zone after short-term nonlinear elastic deformation without a plastic platform stage. The compression deformation resistance in the through-thickness direction is obviously stronger than that in the in-plane direction at a given porosity. The compression strength and the anisotropy both decreased with increased porosity. The compression properties are anisotropic, which also result in different energy absorption efficiencies of the two directions. The relationship between the porosity and the energy absorption efficiency is not monotonically increasing or decreasing, but with the change of porosities, there is an optimal porosity, which has relatively high-energy absorption efficiency.

Production and Anisotropic Tensile Behavior of Resin‐Metal Interpenetrating Phase Composites

“…As mentioned previously, the stainless steel fibers were distributed randomly, and many sintering joints were formed during the sintering process. For the special process, the preform presents a spatial composite intertexture structure from the surface to the center, resulting in an interpenetrating structure of the stainless steel/resin IPC.…”

“…The porous preforms were produced using the three steps of stainless steel fiber fabrication, mold pressing, and vacuum sintering, as described in our previous work . To begin, short 304 stainless steel fibers 10–15 mm in length were fabricated by cutting 304 stainless steel wire ropes (0.8 and 1.5 mm in external diameter, 90 and 160 µm in fiber diameter, respectively), with self‐developed rotary multi‐cutters.…”

“…To begin, short 304 stainless steel fibers 10–15 mm in length were fabricated by cutting 304 stainless steel wire ropes (0.8 and 1.5 mm in external diameter, 90 and 160 µm in fiber diameter, respectively), with self‐developed rotary multi‐cutters. The self‐developed rotary multi‐cutters and their operational process are described in reference . The short fibers were stochastically placed a specially designed mold and pressed.…”

“…Finally, the preforms were naturally cooled to room temperature in the chamber of the furnace. The average porosity P can be calculated using the quality‐volume method, as described in reference, and the fiber volume fraction in the IPC is 1‐ P .…”

“…Our previous work demonstrated that the microstructure and mechanical behaviors of the preforms and stainless steel fiber/ZA8 zinc alloy composites are anisotropic, and thus the stainless steel/ resin IPCs are expected to present anisotropic properties. A Hitachi S‐3700N scanning electron microscope (SEM) was used to observe the microstructure of the IPCs.…”